Like I always do each winter night, I had filled the Margin Gem's firebox with the largest chunks of wood possible. Usually, I then almost completely close all drafts and dampers so that the fire burns slowly all night long. This assures us of a nice bed of coals to rekindle in the morning, a tank of hot water for our morning showers, and fairly steady heat being emitted in the kitchen all night.
On that particular Friday night, I loaded the stove and then thought that I'd leave the drafts and dampers open for a little while to let the wood ignite better before shutting everything down. Unfortunately, my forgetfulness kicked in, and I went to bed without shutting anything. Thus, the firebox was completely full, and the stove was wide open. This was clearly operator error, and I'm duly embarrassed.
I awoke in the wee hours of the morning to go to the bathroom and thought I'd run downstairs and put some more wood in the stove. I sometimes do this when I know that the fire has had time to burn down enough that there will be room for another piece of wood. When I opened the stairway door into the kitchen, I could immediately tell that the kitchen was much warmer than it ordinarily should have been. This was due to the fact that the fire had burned so rapidly--not due to the chimney fire. When I removed the front lid over the firebox, I was shocked to see that only a few coals remained on the grate where normally there would have been a lot of coals and some as-yet-unburned pieces of wood. That is when I investigated and noticed that the draft, the oven damper, and the chimney damper were all open. I still didn't know that we had had a chimney fire at that point, though.
When I began to rekindle the fire by putting a few pieces of wood on the coals, I immediately noticed that the stove was not drawing correctly, and then I became aware that every time I opened a lid, a little noise came from the stovepipe. That was when I realized that we had had a chimney fire. By that time, the wood that I had just put in the stove had caught fire, and there was sufficient draft to carry away the smoke, so there was not much that I could do except close the oven damper and the draft and let the fire burn itself out so that I could clean and inspect the flue in the morning.
Fortunately, we had cleaned the chimney and stovepipe during the first part of February, so there was not as much creosote accumulated in the flue as there might have been. In my opinion, this is the major factor which kept this event from being a full-fledged disaster. The other thing that helps us is our chimney. The Margin Gem cookstove is vented through the masonry chimney which is original to our 98-year-old-farmhouse, but the chimney has been professionally sealed and lined with a heavy-guage stainless steel lining with quite a bit of space between it and the brickwork. Thus, there is an extra heat barrier between the structure of the house and the flue.
The next morning, I hurried to take the stovepipe down and sweep and inspect the chimney. I didn't snap any photographs because I initially didn't plan on blogging about this event and I was in a huge hurry to get the fire going again because we had a ton of laundry to do and needed it to heat our water.
You might think that a chimney fire would burn away all of the creosote that is in the flue. In my experience, what happens is that the creosote sort of bubbles and puckers so that it actually protrudes into the flue and impedes the draft. It becomes sort of like the carbonized stuff on the floor of your oven after a pie boils over. Because it is so brittle, it is easy to clean out of the chimney.
In my eighteen years of cooking with wood cookstoves, this is the second chimney fire that I have experienced. Both events have some things in common: creosote, a hot fire, and an open oven damper.
|The Margin Gem's oven damper in the open position.|
It is the lower lever on the left with the black sphere on the bottom.
The first one occurred in the summer of 2004 (I remember this because Nancy and I were engaged). I had baked bread in the Qualified on a late spring or summer afternoon, and after the bread came out of the oven, I opened the oven damper to let the heat escape up the chimney rather than heat up the house. I knew that the chimney needed cleaning, but did not dream that a chimney fire would result.
All of this serves to remind me of a short quote from Gladys Dimock that Jane Cooper included in her 1977 book Woodstove Cookery: At Home on the Range: "Except for starting the fire, I always keep the oven damper closed. This prevents the flames from going up the chimney and igniting any creosote. We had a chimney fire once because the damper was left open. Never again."
During summer use, I still open the oven damper when I'm finished cooking to let the heat escape up the chimney, but I'm careful about it. Obviously, keeping creosote at a minimum is quite important too.
If you discover that you have an active chimney fire, the first thing to do is close all dampers and drafts on your stove because you want to deprive the fire of its source of oxygen. This was sufficient to extinguish the 2004 chimney fire.
We keep a chimney fire extinguisher handy at all times. This is a stick-shaped thing somewhat similar to a flare that is activated and put into the firebox. I've never used it, though.
Another method for extinguishing a chimney fire which I've only read about is to put water-soaked newspapers on top of the fire in the firebox. The idea is that the heat of the fire will cause the water in the papers to turn into steam, which will then travel up the chimney and extinguish the burning creosote.
If any of you have further information about chimney fires, please share it in the comments below. We all should want to be responsible woodburners because operating our stoves safely results in fewer hazards and insurance claims, which in turn keeps us safe and our insurance rates low.